HID: qvr: Fix for potential heap buffer overflow

Value of sensor->calib_data_len could be changed between
the reads causing potential heap buffer overflow.
When a 0 length is passed to kzalloc, non-NULL pointer
is returned, but this pointer is invalid.

Change-Id: Ie6ed76f63f7a433728e2292222ba9716c3a02635
Signed-off-by: rbandi <rohitbandi@codeaurora.org>
This commit is contained in:
rbandi 2020-11-20 07:15:09 -08:00
commit 2c4dadbbbc

View file

@ -145,7 +145,7 @@ static int read_calibration_len(void)
return sensor->calib_data_len;
}
static uint8_t *read_calibration_data(void)
static uint8_t *read_calibration_data(int calib_data_len)
{
struct qvr_external_sensor *sensor = &qvr_external_sensor;
__u8 *hid_buf;
@ -153,7 +153,7 @@ static uint8_t *read_calibration_data(void)
uint8_t read_len;
uint8_t *complete_data = NULL;
if (sensor->calib_data_len < 0) {
if (calib_data_len <= 0) {
pr_err("%s: calibration data len missing\n", __func__);
return NULL;
}
@ -165,13 +165,13 @@ static uint8_t *read_calibration_data(void)
hid_buf[0] = QVR_HID_REPORT_ID_CAL;
hid_buf[1] = QVR_CMD_ID_CALIBRATION_BLOCK_DATA;
complete_data = kzalloc(sensor->calib_data_len, GFP_KERNEL);
complete_data = kzalloc(calib_data_len, GFP_KERNEL);
if (complete_data == NULL) {
kfree(hid_buf);
return NULL;
}
total_read_len = 0;
while (total_read_len < sensor->calib_data_len) {
while (total_read_len < calib_data_len) {
sensor->calib_data_recv = 0;
ret = hid_hw_raw_request(sensor->hdev, hid_buf[0],
hid_buf,
@ -193,7 +193,14 @@ static uint8_t *read_calibration_data(void)
return NULL;
}
read_len = sensor->calib_data_pkt[2];
if (total_read_len > sensor->calib_data_len - read_len) {
if (read_len <= 0) {
pr_err("%s:Viewer returned non positve length\n", __func__);
kfree(hid_buf);
kfree(complete_data);
return NULL;
}
if (total_read_len > calib_data_len - read_len) {
kfree(hid_buf);
kfree(complete_data);
return NULL;
@ -543,6 +550,7 @@ static long qvr_external_sensor_ioctl(struct file *file, unsigned int cmd,
struct qvr_external_sensor *sensor = &qvr_external_sensor;
struct qvr_calib_data data;
uint8_t *calib_data;
int lcalib_data_len;
void __user *argp = (void __user *)arg;
int ret;
@ -568,13 +576,14 @@ static long qvr_external_sensor_ioctl(struct file *file, unsigned int cmd,
return -EFAULT;
return 0;
case QVR_READ_CALIB_DATA:
lcalib_data_len = sensor->calib_data_len;
sensor->calib_data_recv = 0;
calib_data = read_calibration_data();
calib_data = read_calibration_data(lcalib_data_len);
if (calib_data == NULL)
return -ENOMEM;
data.data_ptr = (__u64)arg;
if (copy_to_user(u64_to_user_ptr(data.data_ptr), calib_data,
sensor->calib_data_len)) {
lcalib_data_len)) {
kfree(calib_data);
return -EFAULT;
}